feat: add CORS support with user-sourced trusted origins from .env

package.json

@@ -4,6 +4,7 @@
     "description": "Your go-to place for short and memorable URLs.",
     "type": "commonjs",
     "devDependencies": {
+        "@types/cors": "^2.8.19",
         "@types/express": "^5.0.6",
         "@types/jsonwebtoken": "^9.0.10",
         "@types/lodash": "^4.17.21",
@@ -13,6 +14,7 @@
         "typescript": "^5.8.2"
     },
     "dependencies": {
+        "cors": "^2.8.5",
         "dotenv": "^17.2.3",
         "express": "^5.1.0",
         "jsonwebtoken": "^9.0.3",